Here we present 26,928 data points of planktonic foraminiferal shell sizes from 49 samples belonging to core SAT-048A, recovered from the western South Atlantic, spanning the 5-43 ka time interval. Sizes were extracted using imaging software. For the images acquisition, tests were positioned with their umbilical side facing upwards. Photographs were manually taken using the Zen 2.6 lite software (blue edition) and a Zeiss stereomicroscope, model Discovery V8 Stereo with an Axiocam 105 color digital camera attached. To measure the tests, we used the software ImageJ (Abràmoff et al., 2004; version 1.53c) freely available at https://imagej.nih.gov/ij/. To obtain the measurements in ImageJ, the images were segmented, first converting them to grayscale (8 bits) and then to binary images. Data are shown as cross-sectional area in squared micrometers.This dataset presents size measurements belonging to 4 taxa of planktonic foraminiferal shells. The analysed species are Globigerinoides ruber albus, Globigerinita glutinata and Globigerina bulloides. In addition, the Partial assemblage covers the three mentioned species plus Neogloboquadrina pachyderma, Globorotalia inflata, Globigerinella calida, Globigerinoides ruber ruber. Area was measured as cross-sectional are in squared micrometers.